GWD Survey Tool Magnetometer Offset Correction for Azimuth Accuracy
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Solution Overview
Problem
Existing survey tools used in gyro-while-drilling (GWD) applications face inaccuracies in determining wellbore trajectory due to non-stationary conditions during drilling, which affect gyroscopic and magnetic measurements, leading to errors in azimuth and inclination calculations.
Innovation Solution
A GWD survey tool that acquires gyroscopic and magnetic data at discrete positions within the wellbore, determines an offset value for the magnetometer based on gyroscopic and initial magnetic data, and uses this offset to calculate accurate magnetic azimuth values, thereby improving trajectory determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gyroscopic sensors and magnetometers are used to determine wellbore orientation, then directional information can be obtained, but measurement inaccuracies occur due to non-stationary conditions during drilling
Solution Approach 1:
The patent introduces an intermediary computational process that uses gyroscopic data to determine correction values for magnetic field measurements. The gyroscopic measurements serve as a reference frame to correct magnetometer readings, effectively mediating between the two measurement systems to produce accurate azimuth and inclination values even during non-stationary drilling conditions
Solution Approach 2:
The system implements feedback by continuously comparing gyroscopic and magnetic measurements, calculating correction values based on the gyroscopic reference frame, and applying these corrections to subsequent magnetic field measurements. This closed-loop approach maintains measurement accuracy despite changing drilling conditions
2Measurement precision
If magnetometer measurements are taken during drilling, then magnetic azimuth data can be acquired, but offset errors affect the accuracy of azimuth determination
Solution Approach 1:
The patent applies preliminary action by calculating correction offsets using gyroscopic data before final azimuth determination. The system first establishes the gyroscopic reference frame, then uses this frame to determine and apply correction values to magnetic field measurements, ensuring accurate azimuth calculation even in the presence of magnetometer offsets
Solution Approach 2:
The system changes the reference parameter for magnetic measurements by using gyroscopic data to define a corrected reference frame. Instead of relying on raw magnetic field data alone, the system transforms the magnetic measurements into the gyroscopic reference frame, effectively changing the parameters used for azimuth calculation to eliminate offset errors
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances the accuracy of wellbore trajectory determination by compensating for measurement errors, ensuring precise alignment with planned trajectories and facilitating effective placement of drilling equipment.
Implementation Method 1
acquire first magnetic data using a magnetometer of the GWD survey tool
Implementation Method 2
acquire gyroscopic data using one or more gyroscopic sensors of a gyro-while-drilling (GWD) survey tool
Data Source
AI summary
Various implementations directed to a system and method for using a magnetometer in a gyro-while-drilling (GWD) survey tool are provided. In one implementation, a method may include acquiring gyroscopic data using gyroscopic sensors of a GWD survey tool while the tool is disposed at a first position within a wellbore. The method may also include acquiring first magnetic data using a magnetometer of the GWD survey tool while the tool is disposed at the first position. The method may further include determining an offset value for the magnetometer based on the gyroscopic data and the first magnetic data. The method may additionally include acquiring second magnetic data using the magnetometer while the tool is disposed at second positions within the wellbore. The method may also include determining magnetic azimuth values for the tool disposed at the second positions based on the second magnetic data and the offset value.